As　the　core　of　cathode　materials,　sensitive　metals　play　important　roles　in　the　optimization　of　acetate　production　from　carbon　dioxide　(CO2)　in　microbial　electrochemical　system　(MES).　In　this　work,　iron　(Fe),　copper　(Cu),　and　nickel　(Ni)　as　sensitive　metal　cathode　materials　were　evaluated　for　CO2　conversion　in　MES.　The　MES　with　Fe-electrode　as　a　promising　electrode　material　demonstrated　a　superior　CO2　reduction　performance　with　a　maximum　acetate　accumulation　of　417.9　±　39.2　mg/L,　which　was　1.5　and　1.7　folds　higher　than　that　in　the　Ni-electrode　and　Cu-electrode　groups,　respectively.　Furthermore,　an　outstanding　electron　recovery　efficiency　of　67.7　%　was　shown　in　the　Fe-electrode　group.　The　electron　transfer　between　electrode-suspended　sludge　was　systematically　cross-evaluated　by　the　electrochemical　behavior　and　extracellular　polymeric　substances.　The　Fe-electrode　group　had　the　highest　electron　transfer　rate　with　0.194　s-1　(kapp),　which　was　17.6　and　21.5　times　higher　than　that　of　the　Cu-　and　Ni-electrode　groups,　respectively.　Fe-electrode　was　beneficial　for　reducing　electrochemical　impedance　between　the　electrode　and　suspended　sludge.　Additionally,　redox　substances　in　extracellular　polymeric　substances　of　the　Fe-electrode　group　were　increased,　implying　more　favorable　electron　transport　dynamics.　Simultaneously,　enrichments　of　functional　bacteria　Acetoanerobium　and　increased　key　enzymes　involved　in　the　carbonyl　pathway　of　the　Fe-electrode　group　were　observed,　which　also　promoted　CO2　conversion　in　MES.　This　study　provides　a　perspective　on　evaluating　the　promising　sensitive　metal　electrode　material　for　the　process　of　CO2　valorization　in　MES　and　offers　a　reference　for　the　subsequent　electrode　modification.　©　2025